Managing fungal diseases of grapevines
CALS Impact Statement
The primary focus of this project is to support the existing and expanding grape and wine industries in New York and other states east of the Rocky Mountains, by increasing the abilities of producers and their advisors to manage infectious diseases that limit profitability and preclude sustainable production if not addressed adequately. The project has three primary foci. First, Extension education, synthesizing and intelligibly presenting the information that producers and advisors need to know in order to manage these diseases efficiently, effectively, and economically. Second, applied research (and limited basic research) to provide new information that will serve as the basis for improved management programs for traditional diseases and identify the causes and controls for new diseases as they arise. And third, undergraduate and graduate education at Cornell's College of Agriculture and Life Sciences, to train the next generation of vineyard managers and their advisors.
Although grapes have been cultivated in New York and other eastern states for nearly two centuries, the industry has traditionally focused on varieties of vines native to this region. However, demand for such varieties (e.g., Concord, Catawba, Niagara) has decreased steadily in recent years, resulting in lower prices and the need to minimize production costs, including those for disease management. In contrast, demand and prices for premium wine grapes have increased steadily, driven by the rapid expansion of local wine industries and associated agrotourism. However, premium wine grape varieties (e.g., Chardonnay, Riesling, Pinot Noir) derive primarily from a single grape species native to Europe, and such varieties have little resistance to the major disease organisms native to our region. Thus, traditional disease management programs developed for native American varieties are not only biologically inadequate for premium wine grapes, but the consequences of poor control on the latter are magnified by their increased value. Furthermore, many producers of these varieties have no farm background and little to no experience with plant disease control on a high-value crop. Therefore, this project has been undertaken to both help producers of native varieties decrease their production costs while maintaining adequate disease control; and (II) develop appropriate management programs for high-value wine grapes together with educational programs for their implementation.
Research projects were implemented to study the biology and management of the five major fungal diseases, two major viral diseases, and one major bacterial disease of grapes common throughout the northeastern and midwestern states. Specific areas of research focused largely on the applied biology and integrated management of these diseases, with two primary emphases: (1) how climate, grapevine physiology, and viticultural practices impact disease development and management; and (2) the activities of important fungicides and biological control agents used in grape production, in order to maximize the efficiency of their use and reduce the economic and environmental costs associated with such. Additionally, more basic research was initiated to understand the mechanisms of pathogen behavior and the potential for disease control through non-traditional breeding. Growers and advisors received regular educational programming through a variety of oral presentations, printed and electronic media, and in-person consultations; in 2006, this included 19 oral presentations to nearly 2,000 individuals and 16 written publications. In the past 3 years, oral presentations have also been made to stakeholders in 12 states outside New York; this information quality is furthermore reflected by invitations to speak to producers in four foreign countries. In 2006, a new undergraduate course, Grape Pest Management, was initiated to instruct the next generation of vineyard managers and advisors.
Supported by the results of our research and extension programs, producers of native grape varieties have typically reduced their fungicide spray programs by approximately three applications per year over the past 10-15 years, resulting in an annual savings of approximately $1.8 million across the 20,000 acres of these grapes in New York alone. Because high-value wine grapes have only a short history of production in most regions, similar comparisons are difficult to make. Nevertheless, a typical annual cost for disease control in these vineyards has been estimated at nearly $500 per acre, and the cost of a poorly-controlled, ubiquitous disease such as powdery mildew is approximately $6,000 per acre (complete loss of 4 tons/acre x $1,500/ton). Assuming a 10 percent reduction in costs brought about by increased efficiencies due to our programs, this translates to approximately $250,000 per year across the 5,000 acres of such grapes in New York. Furthermore, an assumption that our efforts have resulted in merely a 5 percent annual reduction in fruit lost to disease provides an annual savings of approximately $1.1 million in farmgate value, and up to $11 million in retail wine value (applying the common formula for grape:retail wine prices). A similar value could be applied to the economic benefits provided to nearby regional states (e.g., Virginia and Pennsylvania), which in aggregate have a similar number of acres of similar varieties relative to New York.